JPS6357222A - Manufacture of hollow body - Google Patents

Abstract

PURPOSE:To obtain an airtight seal between hollow bodies and to prevent generation of burrs on a joint, by a method wherein after both split pieces of the hollow body have abutted against each other, they are unified by molding a filling material by filling the same into a casting long groove through a casting port. CONSTITUTION:Long grooves 3, spare long grooves 4, 4 and a casting port 2 are kept molded respectively on the inside of the center of a connecting part 5 connecting a plurality of hollow bodies with each other, both sides of the long groove 3 and further appropriate position of one side of the long grooves. The long groove 3 having the casting port 2 on an appropriate position of the center part of a connecting part 5 by abutting both split pieces against each other and enclosed spare long grooves 4, 4 are set up within a mold by forming them and then post-forming is performed by casting a filling material 7 through the casting port 2. With this constitution, as the long groove 3 for casting the filling material is running within the connecting part, joining can be performed so that a post-forming member is not visible from the outside. Even if the filling material flows out through an abutting surface of the long groove 3 with pressure, ejection of burrs up to the inside of the hollow body can be prevented by only driving the burrs within the spare long grooves 4, 4.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a method suitable for manufacturing a hollow body having a complicated three-dimensional shape, such as an intake manifold, and is applicable to the field of internal combustion engine manufacturing, It is particularly used in the automobile industry.

[Conventional technology]

As a manufacturing method for plastic hollow bodies with complex shapes that change three-dimensionally, such as intake manifolds used in automobile engines, the hollow body is divided into two parts, a divided-shaped product is formed by preforming, and each divided piece is A method was developed in which the outer skin was post-molded (injection molded) after being placed in each mold, and the molds were then tightened to cover the joints.

What is shown in Figures 5A to 5D is
It was disclosed as No. 6, and each divided pipe body 11゜1
1 are held in contact with each other, and a synthetic resin layer 20 is formed by post-molding so as to cover the outer periphery of the flanges 17, 17.

The one in Fig. 5C shows that the required parts of the inner surface of the protruding flange are also filled with post-molded resin for reinforcement, and the one in Fig. 5D shows that when the dimension of the abutting surface 16 of the divided piece is large, there is no contact with the intermediate part. A gap 16 is formed to ensure that both ends of the abutting surfaces are tightly joined due to excessive pressure caused by the gap 16. Moreover, FIG. 5A discloses that the connecting member (metal member) 9 is joined together at the same time as the post-forming.

[Problem that the invention seeks to solve]

In the above-mentioned molding, for example, when a plurality of pipes are arranged in parallel, it is necessary to form a space between each pipe and cover the outer periphery of the flange on both sides of each pipe. If a seal is required between the hollow bodies (pipes), a certain distance space must be formed between the hollow bodies.

In addition, in post-molding in the form shown in Figures 5A, 5B, and 5C, deformation and movement occur due to the injection pressure and resin flow of post-molding, resulting in deformation and deformation from the contact surface, which requires precision. This was disadvantageous for the production of products.

[Means and operations for solving the problem] When pre-forming a divided piece in which a plurality of hollow bodies are connected at a connecting portion, as shown in FIGS. 1 and 3A, the connecting portion 5 is A long groove 3 is formed on the inner surface of the center, and preliminary long grooves 4, 4 are formed on both sides of the long groove 3.
The injection ports 2 are formed in appropriate positions in the long grooves 3 on both sides,
Both divided pieces are brought into contact with each other to form a long groove 3 having an injection port 2 in a proper position in the center of the connecting part 5, and a pre-sealed preliminary long groove 4, 4, and set in the mold as shown in Fig. 1. and then inlet 2
A filler 7 is injected into the mold, and the molding is carried out as shown in FIG. 3B.

Since the long groove 3 for filling material injection runs inside the connecting part,
The post-formed material can be joined without any unsightly appearance exposed from the outside. Further, even if the filler flows out from the abutting surface of the long groove 3 due to pressure, it only creates a burr within the preliminary long grooves 4, 4, and can prevent the burr from protruding to the inner surface of the hollow body.

〔Example〕

[Example 1] As is clear from FIGS. 1 to 3B, corresponding divided pieces in the form of a plurality of half pipes 1 connected by a connecting part 5 were each preformed with glass fiber reinforced nylon 6 with a general wall thickness of 51. . The connecting part between each half-vibe 1 has a long injection groove 3 in the center.
Preliminary long grooves 4, 4 having a depth of about 172 times the length of the long groove 3 were provided on both sides of the half pipe in the middle of the thickness of the half pipe. In addition, one injection port 2 was provided in the longitudinal center of the long injection groove 3 of one of the divided pieces.

Next, each divided piece was dimensioned as shown in FIG. 1 and brought into contact and integrated, and after tightening with a mold, nylon 66 was injection molded from the injection port 2 and filled into the long injection groove 3 at a constant pressure.

In the obtained parallel pipe parts, the nylon 6 of the preforming material and the nylon 66 of the filler 7 used for post-forming are compatible, and the nylon 66 of the filler 7 is compatible with the nylon 66 of the preforming material.
Since it has a higher melting point than the preformed material, part of the surface of the preformed material melts during post-forming, and the filler 7 solidifies integrally. Integrated under mechanical strength. Note that resins having similar molecular structures generally have good compatibility with each other.

In addition, the filler 7 is injected at a considerably high pressure during post-molding.
Although the paris injected into the pipe 13, the paris that slightly flowed out from the contact surface 6 of the divided piece only protruded into the preliminary long groove 4, and did not generate any paris on the inner surface of the pipe as a final product.

[Example 2] As is clear from Figures 4A and 4B, the connecting portion 5 of each divided piece
It was manufactured in the same manner as in Example 1, except that injection ports 2°2 were provided in the long injection grooves 3 from the outer surface.

In the obtained product, as shown in FIG. 4B, protrusions 7' of the injection filler 7 were formed on both sides of the connecting part 5, but this did not cause any problem in the use of the final product; It even helped strengthen the bond between the two. Other effects were the same as in Example 1.

Although the manufacturing of plastic products has been described in detail in each embodiment, the present invention can be applied to a wide range of materials that can be molded using a mold, the relationship shape of the long injection groove 3 and the preliminary long groove 4, and the arrangement of the injection port 2. It will be obvious to those skilled in the art that the shape and the like can be modified in various ways depending on the material to which it is applied.

〔Effect of the invention〕

It becomes possible to separately mold a multi-pipe product in which the pipes are closely arranged in parallel, and it becomes possible to manufacture a long-cast product with a plurality of hollow bodies having airtight seals between the hollow bodies.

When the divided preforms are integrated by post-forming, no cracks are generated on the joint surfaces.

[Brief explanation of drawings]

FIG. 1 is a sectional view taken along the line A--A in FIG. 2A showing an embodiment of the present invention. FIG. 2A is a partial plan view of an embodiment of the present invention, and FIG.
The figure is a side view in the B direction of FIG. 2A. FIG. 3A is a sectional view of the main part before joining in the present invention,
FIG. 3B is a sectional view of the main part after bonding and molding. FIG. 4A is a diagram corresponding to FIG. 3A in another embodiment, and FIG. 4B is a sectional view of a main part of the one shown in FIG. 4A after bonding and molding. 5A, 5B, 50, and 5B are partial sectional views for explaining the prior art, respectively. 1: Half pipe, 2: Inlet, 3: Long injection groove, 4: Preliminary long groove, 5 Two connecting parts, 6: Contact surface, 7: Filler. Figure 5A Figure 5B Figure 5c - To stone A, 11'/-'----°"14
...Preliminary long groove 5...Connection part

Claims (1)

[Claims] 1. A long injection groove (3) with an injection port (2) in a hollow body connection part (5) of a preform in which divided hollow bodies (1) are arranged side by side.
) are integrally molded, and after abutting both divided pieces, a filler (7) is post-molded from the injection port (2) into the injection long groove (3) and integrated. 2. The manufacturing method according to claim 1, wherein compatible materials are selectively used for the material of the preform and the filler for the post-forming.